Hello everybody! So I've got a rhythmic, knocking noise from the pass front when driving between 10-30mph. Also truck and driveline are warm during noise. When slowing, the noise reduces in tempo. No noise when truck is in neutral. I'm thinking noise is in front diff because the driveshaft is greaseable and I grease it about every 15k.

I've posted a video of some shaft and diff play and I don't know if it's normal...

Is that amount of play normal? Should I grease the shaft more often? Do y'all have any ideas? I'm going to take a video of the noise happening and post it too. Also, this has been going on for about 10k and started out very low in volume in the beginning.
Here is the noise when moving:

 

Couldn't hear clearly from second video, but from first one I can tell you some of slack is from your transfer case, even though your diff is also pretty loud & has good amount of slack, when was last time you changed diff oil's,? If not recently, then change diff oils & see if there is lots of shaved metal in it or not,? Some ppl use 75w140 gear oil in worn out diff's to quiet them down a little,, not a bad idea to change Trancfer case oil too (for this most ppl will go with what factory recommended 75w90), as for driveshaft grease I think every 15k is not soon enough & you have to do more often, (I do with every oil change),,,
By the way, is your truck all cromed out,? (What I noticed from 2nd video)

 

Thank you for the response. No chrome. That's all black. I have the fender flares removed.

I changed diff fluids about 20k ago. I'm going to change them again next week

 

Sounds more like an engine noise to me

It appears to change with the speed of the engine and not the speed of the truck.

 

well..there is definitely an engine noise in the second video, but right now we are just worried about the secondary knocking that is at a lower volume in that video.
You might have to turn up the video and listen more intently around the 10 sec mark.

but anyway, I KNOW the noise i'm currently working on is coming from the diff or the front shaft.

Engine noise is looking like a sleeve issue, but i'm not fixing that till the engine siezes. No, I'm not kidding.

 

First video is of knocking noise with you manually rotating drive shaft from beneath and then rotating hub?

If so obviously sounds as way too much play. Have you removed shaft and checked to see if your well greased joints may simply be falling apart? Doesn't appear so so but should be removed for check and further troubleshooting. While shaft removed rotate diff input and listen/feel for play.
......

 

Thank you! No I have not removed the shaft yet. So far my plan is to change diff fluid and check for metal shavings etc first. Then I'll remove the shaft and check as you suggested

 

just curious...at that point how much it will cost to do a rebuild?...

I'm @ the 110K just waiting for the knocks to show up!

 

Well, not to get too far off topic...but I've got a rough quote from a local LR shop here starting at 7k with tophatted block done by a local machinist. This is engine has never been opened and has 206k on it. I'm going for 250k. It has a good chance of getting there. The noise stops after 2 minutes of warm up...so I think its still got more to go.

 

Not even the notorious head gasket done?
Very impressive, you must really took maintenance seriously!